1. Field of the Invention
The present invention relates to an interactive system, and more particularly, to a control device and a control method for an image display.
2. Description of the Related Art
A conventional cursor control method, such as the Taiwan patent publication no. 200540687, entitled “apparatus for cursor control and method thereof”, discloses a method for cursor control using a hand-held device. First, an optical device of the hand-held device is used to detect a movement. Afterward, a position difference is calculated according to the detected movement. Then, the hand-held device transmits the position difference to a specific device wirelessly to accordingly control cursor activity thereon, and operate an application on the specific device according to the cursor activity. However, when the optical device is used to sense an image area, a distance between the optical device and the object to be captured, and a rotation degree of the optical device during capturing images all influence the image position on the sensing array. If the calibration is not made simultaneously, the cursor will be likely to be inexactly controlled. Furthermore, because the image captured by the optical device contains all objects falling within the field of view thereof, the image recognition process is more complicated.
In order to solve the above problem, the copending Taiwan patent application no. 095116011, entitled “POINTER POSITIONING DEVICE AND METHOD” and Taiwan patent application no. 095149408, entitled “CURSOR CONTROLLING METHOD AND APPARATUS USING THE SAME” are provided. These inventions are to arrange at least one reference point to generate an infrared spectrum signal with a wavelength of about 940 nm and to arrange an infrared pass filter on an image sensor to remove the light out of the infrared spectrum thereby simplifying the image recognition process. Further, these inventions are to control an image display according to the change of the images of reference point, such as displacement, captured by the image sensor. The image sensor is immune to the influence of the light generated by the fluorescent lamp (wavelength 350-750 nm) commonly used for indoor illumination. However, the image sensor is prone to the influence of the light generated by the halogen lamp (wavelength 350-1100 nm). Therefore, when a halogen lamp is placed close to the reference point, images captured by the image sensor equipped with the infrared pass filter will contain both the reference point and halogen lamp. This will cause a rear-end image processor to make an inexact recognition and therefore fails to exactly control the image display. Moreover, the control device is also prone to the influence of sunlight.
In view of the above, there is a further need to improve the conventional control devices for image display in order to increase the control precision of the control devices.